net: added sendfile support for io.SectionReader

net: added sendfile support for io.SectionReader

3 points to note. SectionReader now exports ReaderAt in same
way as the LimitedReader. Offset and Remaining bytes use
methods instead as it seemed cleaner that way. General support
for Darwin was added which makes it identical to dragonfly and
freebsd (should possibly be refactored into one). The test for
linux uses similar approach to the net/http/fs_test.go which I
know is not ideal.
Fixes issue 6374.

[bradfitz, 2014-03-05 19:58:10]

I think this is probably too large and invasive for Go 1.3 (notably
invasive: it has API changes). We're past the March 1st new-code freeze,
too, and in stabilization mode.

I know Issue 6374 is marked Release-Go1.3, but I think that was with the
assumption that the fix was trivial.

We might have to wait 3 months for this, in the Go 1.4 cycle, unless Russ
or others really want to see this go in.



On Wed, Mar 5, 2014 at 6:13 AM, <markus@distinctive.co> wrote:

> Reviewers: golang-codereviews,
>
> Description:
> net: added sendfile support for io.SectionReader
>
> 3 points to note. SectionReader now exports ReaderAt in same
> way as the LimitedReader. Offset and Remaining bytes use
> methods instead as it seemed cleaner that way. General support
> for Darwin was added which makes it identical to dragonfly and
> freebsd (should possibly be refactored into one). The test for
> linux uses similar approach to the net/http/fs_test.go which I
> know is not ideal.
> Fixes issue 6374.
>
> Please review this at https://codereview.appspot.com/69870051/
>
> Affected files (+303, -9 lines):
>   M src/pkg/io/io.go
>   A src/pkg/net/sendfile_darwin.go
>   M src/pkg/net/sendfile_dragonfly.go
>   M src/pkg/net/sendfile_freebsd.go
>   M src/pkg/net/sendfile_linux.go
>   M src/pkg/net/sendfile_stub.go
>   A src/pkg/net/sendfile_test.go
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "golang-codereviews" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to golang-codereviews+unsubscribe@googlegroups.com.
> For more options, visit https://groups.google.com/groups/opt_out.
>

[bradfitz, 2014-04-06 15:56:55]

https://codereview.appspot.com/69870051/diff/20001/src/pkg/io/io.go
File src/pkg/io/io.go (right):

https://codereview.appspot.com/69870051/diff/20001/src/pkg/io/io.go#newcode471
src/pkg/io/io.go:471: func (s *SectionReader) Offset() int64 { return s.off }
think you'd want s.off - s.base here anyway.  Or you'd at least want to explain
which offset you mean in the docs.